| 摘要 |
PURPOSE:To surely read out data by selecting an optimum clock out of plural clocks having different phases when a phase error between a receiving signal and an office clock selected for a self-office exceeds a prescribed value. CONSTITUTION:An output 17 generated from an edge detecting circuit 16 and inputted to a receiving packet 15 is inputted to a monostable multivibrator 18. An FF 42 reads out the input of the packet 15 synchronously with an output 19 of the multivibrator 18 and outputs NRZ data 34. An FF 49' reads out the NRZ data 34 at the rise of a sampling clock 76 outputted from a clock switching circuit 75 and finally outputs NRZ data 41' through an FF 63. The sampling clock 76 is phase-compared with the output 19 of the multivibrator 18 by a phase difference detecting circuit 79 and a clock selecting part 73 selects one of plural clocks 72 obtained from a multilayer clock forming part 71 in accordance with the difference of the phases and sends the selected clock to a clock switching circuit 75. |
